Abstract: We present a search for technicolor particles decaying into $b\bar b$, $b\barc$ or $b\bar u$ and produced in association with $W$ bosons in $p\bar p$collisions at $\sqrt{s}= 1.96 \mathrm{TeV}$. The search uses approximately $1.9\mathrm{fb}^{-1}$ of the dataset accumulated in the CDF II detector at theFermilab Tevatron. We select events matching the $W$ + 2-jets signature andrequire at least one jets to be identified as $b$-quark jets. In the case ofexactly one vertex $b$-tagged events, we apply a neural network flavorseparator to reject contamination from charm and light quark jets. The numberof tagged events and the invariant mass distributions of $W+2$ jets and dijetsare consistent with the Standard Model expectations. We succeed to set a large95% confidence level excluded region on the $\pi {T}$ mass v.s. $ ho {T}$ massplane.